Question

When phenol reacts with dilute nitric acid at room temperature, the major product obtained is

• A. p-nitrophenol
• B. m-nitrophenol
• C. 2,4,6-trinitrophenol
• D. o-nitrophenol

Hint:

When phenol reacts with dilute nitric acid, the nitro group usually enters the meta position due to the electron-donating effect of the hydroxyl group.

Answer 1

The Correct Option is B

Step 1: Understanding the electrophilic substitution of phenol.
When phenol reacts with dilute nitric acid, the nitronium ion (NO\(_2^+\)) attacks the phenol ring, and the product formed depends on the position of the substituent on the ring. At room temperature and with dilute nitric acid, the nitro group typically substitutes at the meta position due to the electron-donating nature of the hydroxyl group.
Step 2: Analyzing the options.
(A) p-nitrophenol: This is not the major product as the nitro group generally enters the meta position in dilute nitric acid.
(B) m-nitrophenol: This is correct. The major product is m-nitrophenol, formed by electrophilic substitution at the meta position.
(C) 2,4,6-trinitrophenol: This product is formed under more concentrated nitric acid conditions, not dilute.
(D) o-nitrophenol: This is incorrect as the nitro group does not preferentially enter the ortho position in this reaction.
Step 3: Conclusion.
The correct answer is (B) m-nitrophenol.